Arrangement for tuning parallel wire lines



.Jqne 16, 1942. RYMEHLER y 2,286,428

ARRANGEMENT NOR TUNING' PARALLEL WIRE LINES Filed June i4, 14940 y Gttomeg vPatented June 16, 1942 ARRAN GEMEN T Germany,

FOB TUNING PARALLEL LINES Paul Mehler, Berlin,

asslgn'or to Fides Gesellschaft fur die Verwaltung und Verwertung von gewerblichen Schutzrechten, m. b. H., Berlin, Germany, a corporation of Germany "Application June 14, 1940, Serial No. 340,538

In Germany March 27, 1939 In order to tune Lecher lines it is customary to change the electrical length of the line. It is possible to tune the electrical length of the Lecher line to a denite frequency by moving a shortcircuit strap. Furthermore, it is known to set the resonance frequency ofa parallel wire line by varying the effective dielectric constant in the vicinity of the line. This may be done, for instance, by inserting sectors having a high dielectric constant between the double line.

In the arrangement according to the invention a tuning of a Lecher line is realized by varying the eiective permeability in the vicinity of the line. For this purpose suitable ferrous magnetic materials are employed which are so devised that they have but low losses even when used in ultra-short Wave systems.

The variation of the eiective permeability of the medium existing in the vicinity of the line can be realized in various Ways. Th'us, suitable materials in the vicinity of the .line may be arranged on the line by way of Stringing or piling them on the line. It is also possible to dispose suitable materials near the double line or to turn or slide them in between the double line. In this manner Lecher lines can be tuned without varying their physical length. While by way of Stringing-on, or piling on, primarily singular invariable adjustments can be accomplished, the

movability of the pieces which are brought near,

or are turned inwards, or slid inwards, renders possible a continuousy variable tuning.

A further possibility resides in surrounding the line'completely or partially with a magnetic material whereby the pieces formed from the lferrous magnetic work material are xedly secured, and the variation of the effective permeability is brought about by the use of a direct current which produces a basic flux variable density in the magnetic material. This aiords an especially accurate adjustment in view of the fact that no mechanically movable parts are provided. Furthermore, this manner of tuning has the advantage thatl the operator need not be in the proximity of the line. Hence, this arrangement is well suited for stations which are remotely controlled.

modulation of the ultra-short wave transmitter can be achieved if modulation currents are employed for thev basic magnetization. This method aiords a very pure frequency modulation in the case of ultra-short wave transmitters, since at the 'tuning arrangement no appreciable power variations of the ultra-short wave transmitter occur.v For modulating ultra-short wave transmitters it has been customary hitherto to vary the operating potentials. Although important variations of the frequency may be produced by varying the operating potentials, there still exists the drawback that through the variations of the operating potentials an important power change occurs, which, of course, results in unwanted amplitude variations. It may thus happen in this case that in addition to the frequency modulation, undesirable amplitude modulations are produced. In employing the arrangement, according' to the invention, an amplitude modulation can be avoided to a great extent since the frequency variaiton does not entail an appreciable change n tentials which are subject to uctuations, a potential can be derived which is applied either as such or through any intermediate devices to the windings for the basic magnetization in the form of a control potential. In this manner an ultrashort wave generator can Ibe constructed whose The arrangement can be employed for tuning ultra-short wave transmitters the oscillatorycircuits of which consist of Lecher lines. If, for instance, the variation of the tuning is carried out by xedly mounting ferrous magnetic materials in'the vicinity of the Lecher line, and the elective permeability of these materials is varied by varying the basic D. C. magnetization, a 55 frequency is constant independently of the uctuations in the operating potentials.

The application of the arrangement, according to the invention, relates to all uses of Lecher lines,to their further developments and modications such as, for instance, to the feed lines of antennas. It is also possible to tune coupling lines between resonancesl capable of oscillation. In a more general way the arrangement, according to the invention, can be utilized in all arrangements in which inductance and capacity are distributed more or less uniformly throughout the length of the line, including the resonances of the dipoles, etc., in contrast with oscillled with ferrous The invention will now be explained in more detail, reference being made to several different examples of construction, a different one being shown in each of the six gures of the drawing.

Figure 1 shows a Lecher-wire system which is tunable by means of ferrous magnetic elements strung over the parallel wires;

Fig. 2 illustrates a method of tuning the line by varying the proximity of certain magnetic elements thereto;

Figs. 3 and 3a illustrate the use of capacitive plates which can be rotated for the purpose of varying the capacitive reactance with respect to the Lecher-wire system;

Fig. 4 shows a tuning system which depends upon varying the permeability of a magnetic field surrounding the conductors;

Fig. 5 shows a transmission system in association with a source and an antenna, and means for tuning the system; and

Fig. 6 shows an application of the basic idea of my invention to a transmission system which is connected to a magnetron oscillator, or the like.

In Fig. 1 the items I and 2 represent a parallel wire line. Suitable ferrous magnetic parts 3-1 can be strung on in this case and the tuning can be varied according to the number of parts used.

In Fig. 2 the bodies 8 and 9 of ferrous magnetic material are arranged below and above the lines I and 2 and can be brought nearer to the line from boh directions.

In Figs. 3 and 3a rotatable parts I0 and II are shown which are mounted on the axles I2 and I3 and can be turned-in between the conductors I and 2. By making the elements Ill and II of ferrous magnetic material they can be caused to react both inductively and'capacitively on the conductors I and 2.

In Fig. 4 there is indicated a variation of the permeability through a basic D. C. magnetization. The conductors I and 2 of the parallel wire line are surrounded by a body I4 of ferrous magnetic material. This body is enclosed by an iron core I5 carrying a coil I6 and serving for attaining an initial magnetization. A direct current is passed through this coil I6, or modulation currents where this arrangement is utilized for the modulation of ultra-short wave generators. When utilizing the arrangement for the purpose of maintaining the frequency of ultra-short wave generators automatically constant a control current passes through the coil I6.

In Fig. 5 the parallel wire lines I and 2 form the connection line between a transmitter I'I and a dipole antenna I 8. For the purpose of tuning the feeder I preferably employ a control member I9 similar to the element I4 in Fig. 4. Not only the feeder but also a tuning of the dipole, or other resonant device can be tuned, and this can generally be accomplished by means of an arrangement according to Fig. 4.

In Fig. 6 there is shown an example of con- Y struction for varying the frequency in the case of retarding field and magnetron transmitters and the modifications thereof. The parallel wire line I and 2 constitutes the oscillatory circuit of a magnetron transmitter. rPhe control device I9 corresponds with element I4 in Fig. 4.

I claim:

1. An arrangement for tuning the parallel conductors of a transmission line comprising a reactance device composed of ferrous magnetic material disposed within the field of influence of said conductors, means for varying the effective parallel conductors may be disposed in close proximity to the elements themselves and may at times be surrounded thereby.

3. An arrangement according to claim 1 in which said device comprises a flat vane, and said means for varying the effective reactance is con'- stituted as a mechanism for adjusting the effective area of said vane which lies within the eld intermediate between said parallel conductors.

4. In combination with a Lecher-wire transmission system, a tuning device comprising a magnetizable element surrounding both conducf tors of said system, a direct current source for rendering said element effectively reactive, and means for controlling the magnetizing force derived from said source, thereby to adjust the reactive effect upon said transmission system.

5. In combination with a two-conductor Lecher-wire transmission system, tuning means arranged to produce a suitable reactance upon said conductors, and means for adjusting the effectiveness of said reactance by varying the magnetic permeability of the medium of which said means is composed.

6. A device according to claim 5, wherein said tuning means is composed of a series of beadlike elements having orifices through which the two conductors are strung.

7. In combination with la two-conductor Lecher-wire transmission system, a relatively fiat tuning device of ferrous magnetic material constituting rotatable means for producing equal reactances in variable degree upon the two conductors of said system, and means for so supporting said device that its plane of rotation occupies a planar zone of reactive influence midway between said conductors.

8. In combination with a. two-conductor Lecher-wire transmission system, a tuning device of'ferrous magnetic material constituting a jacket having two parallel channels through which the conductors .of said .Lecher-wire system are passed, and means for controlling the magnetic ux density in said tuning device, thereby to vary the reactance uponsaid vconductors in like degree.

9. In combination with 'a two-conductor Lecher-wire transmission system, a tuning device .of ferrous magnetic material constituting a jacket having two parallel channels through which the conductors of said Lecher-wire system are passed, said device being movable longitudinally of the conductors and thus constituting means for controlling the magnetic flux density at different points along said Lecher-Wire system, thereby to vary the reactance upon said conductors in like degree.

PAUL MEHLER. 

